Appreciate the quote but obviously others have argued it for years.
As long as your vehicle is an extended interval candidate, it's likely a wash on it's cost vs other oils OTS.
If it's 3k-5k intervals at 2-3 months each, the value isn't there obviously; unless you just love the brand. Nothing wrong with overpaying for oil, necessarily, as it's not a huge cost right?
But, the argument on cost alone becomes marginal, at best, if *safely* extending the interval to a year, 15k-20k etc.
If you're just dumping AMSOIL Signature Series at 3k in a couple of months; for whatever reason, obviously it's a waste.
Folks are so afraid of it performing like an entry level OTS synthetic basically. If that's the case, could there still be this belief "oil is just oil" somewhere in there? Bob would never.

That's why we're here! Some vehicles it may not matter mostly, based on vehicle combined with service conditions.
Still, though, it's a (relatively) small cost over life of ownership and you aren't hurting anything other than some pocket cash even if you don't extend the interval as much as it could be.
Honestly, why is it only the OOP cost folks argue based on anyway? It's low hanging fruit and a tired beaten horse.
You aren't getting worse performance; at a minimum, and you've got headroom if you forgot the oil change last month, etc. It's not a question in product performance! It's a proven product line. (Signature Series)
For me personally, I prefer it for peace of mind these days because my wife became disabled years ago now. One thing you learn to adapt to living with an ill relative is that it's one less thing to worry about or do as frequently. They get more of your time and you have more energy overall.
Just 1 oil change a year. Done. I know the Signature Series can go the year with my used oil analysis to back it. What's not to like?